Will the reformed scheme achieve its objectives?

It depends on what its objectives are! What is the Child Support
Agency for?

Potential objectives

There is no single objective for the reformed CSA for which it is possible
to say "yes, this is the objective of the CSA against which
it should be measured". Whenever an objective is identified,
often as a statement by government, the facts, or analysis, or other statements
and actions by government, give the lie to it.

This, of course, makes it hard to devise a coherent scheme, and equally
hard to verify the legislation and measure the CSA against its objectives!
(This is a different topic from "will the CSA meet its targets?"
These can be localised metrics which don't necessarily relate to policy
objectives. The answer will probably be "if the targets are undemanding
enough, the CSA will often meet them").

Ensuring that children are supported by their parents instead of by
taxpayers

This is a classic reason, with typical questions such as "why should
taxpayers pay for other people's children?" It applies more in some
countries than others, depending on the extent to which the society feels
that children are an individual responsibility or more of a social responsibility.

The UK is somewhere in between the USA, with its emphasis on individual
responsibility, and some European countries, with more of a view that
society has a large part to play. (And some countries see the family as
a whole having a significant part to play). The more the parents have
individual responsibility to pay, the higher the liability is likely to
be, and the more parents there will be who simply can't afford to pay
"their share".

And, of course, taxpayers do pay for other people's children! Apart from
paying for the infrastructure (schools, etc), in the UK the state (taxpayers)
pay Child Benefit, a universal benefit which even rich parents can claim.
A response to the knee-jerk question "why should taxpayers pay for
other people's children?" is "well, you've been doing so for
years without too many complaints, so why stop now?"

In the UK's reformed scheme, perhaps three-quarters of NRPs won't earn
enough for the formula to cause them pay half the regular payments for
a single child. (That isn't saying they couldn't pay, but the force
needed, with penalties and backlash, makes this impractical, or at least
unwise politically). An even smaller proportion will earn enough to pay
their share of 2 or more children.

However obvious this purpose is, it is not the only reason, and actually
probably only has a minor part to play in the UK. The government will
encourage people to take this attitude when it suits them, and will then
simply give away lots of taxpayers' money for other people's children
when it suits them to do that instead! For example, when Working Families
Tax Credit replaced Family Credit, the government stopped trying to reduce
the Treasury's bill (now the tax credit bill rather than the social security
bill, but so what?) And the answer to "can the child support system
achieve this?" is "rarely".

Reducing the social security / welfare bill

This is just a subset of "Ensuring that children are supported by
their parents instead of by taxpayers" above. It is part of the way
the Treasury views the same purpose, when it suits them. They may sometimes
have different objectives that mean that this doesn't suit them. As noted
above, when Working Families Tax Credit replaced Family Credit, the government
stopped trying to reduce the Treasury's bill for that credit. This purpose
was discarded because of a "higher" objective. It was worth
(to the government) spending taxpayers' money on other people's children
in order to get lone parents back to work, because of all the policy and
economic advantages of that. (I am not aware of any consultation on this
- it just happened in the Tax Credit legislation).

This is a narrower purpose than the above ("reduce" not "eliminate"),
so the answer to "can the child support system achieve this?"
is "often". This was the primary purpose of the current child
support system, and after significant losses in the first few years, it
is now being achieved overall. Whether it is enough for any specific purpose
is a different matter - how much do you want to reduce it by?

Relieving child poverty

This interacts with the above purposes. One way of relieving child poverty
is for the state itself to hand out lots of money to parents. Well,
that solved that problem!

Governments don't want to do this, because they believe they won't get
re-elected if they relieve child poverty this way. In the UK, the Child
Benefit bill is about £8 billion - £9 billion per year. Small
Fortunes found that Child Benefit paid about one-fifth of the average
regular spending on a child. Increasing the spend to about £44 billion
per year might just about pay for the children, but would be about 45%
of the total social security bill, and the extra money would be about
£600 per year for every person in the UK - which means a lot more
than this for voter-taxpayers! No, they won't go for this - at least in
one jump.

The degree to which this is acceptable depends on the society. In the
USA the state / taxpayer support is relatively small compared with the
UK, and voter-taxpayers want to keep their tax bill small. The UK has
an intermediate position, with some European countries being willing to
pay more per child. The USA tends to take a "moral" (in some
sense) position, that it is the responsibility of the parents rather than
the state to pay. This is somewhat true in the UK too, hence "why
should taxpayers pay for other people's children?"

Can the problem be solved instead using child support rather than state
benefits / welfare? This is similar to asking "can child support
reduce the social security bill for lone parents to zero?" And the
answer to "can the child support system achieve this?" is "rarely",
for the same reasons. Most NRPs don't earn enough to pay sufficient to
move their children out of poverty by themselves. At most it can only
be one component of reducing child poverty.

Making people feel better

Making PWCs feel better

Some PWCs say something like "I want him to pay something, even
if it is only £5 per week, so that I know he has an ongoing responsibility".
Some want their children to know that the father is still paying. Whether
or not these are good purposes, the child support will normally be able
to achieve these.

Making members of society feel better

Knowing that there is a CSA "to stop deadbeat dads abandoning their
children so that they have to live on the state" probably makes some
people feel better. (Whether it should, given the distortion in that statement,
is another matter!)

Making children feel better

Social engineering of various kinds

Is the child support system intended to change behavior rather than achieve
a simple financial objective? There are various possibilities.

Helping / encouraging the PWC get to work

It wasn't established to do this, although having a £15 disregard
in Family Credit may have helped. The "child maintenance bonus"
in the 1995 Child Support Act could have helped, but appears to have had
little or no effect at all, and perhaps wasn't even understood by PWCs.

But having a total disregard in WFTC, combined with a more generous amount
than Family Credit, plus New Deal for Lone Parents to help seek employment,
means that child support can act as an incentive for people to move from
Income Support to WFTC - it acts like an extra top-up in addition to WFTC.
This works when the NRP earns enough to pay a significant amount. Most
don't.

Helping / encouraging the NRP get to work

If the rule was "pay £X per week whether you can afford it
or not", this may be an incentive (or at least a big stick) to cause
NRPs to earn enough to pay £X. (Although it is also an incentive
for some of them to drop out, disappear, or commit suicide).

Encouraging men and/or women to be more sexually responsible

Women - possibly not.

Men - possibly.

Encouraging parents to share the care of their children

No.

Conclusion

In the last few years, I have moved from the typical childfree-taxpayer's
view "why should I pay for other people's children?" to a realisation
that every future UK government is going to force me to do so anyway!
The real questions are - "how much?" (which may not vary a lot
from one government to another) and "in what way?". The latter
question is a key policy & political question. Will my taxes pay directly
for the child's consumables, or will they instead provide infrastructure
(childcare facilities, say) and incentives for the parents to earn more
to take on more of their own responsibilities towards their children?

Economically active parents, net contributors to the Treasury, able to
support their children themselves, setting a good example, buying services
such as childcare which keep others employed too - this is an aim of most
governments. It appears to be a worthwhile use of my taxes.

The child support system should be designed to help, or at least not
hinder, both separated parents become (more) economically active. And
when they are economically active, it should supplement the earnings of
whoever cares for the children at any time to bring the child out of poverty.
It shouldn't not be intended primarily to try to relieve child poverty
on its own, because it won't succeed often enough.